Multi-stage transmission for vehicle

A multi-stage transmission for a vehicle, comprising:

• a first to fourth planetary gear devices having three rotary elements, respectively;
• six shifting elements configured to variably provide frictional force;
• and
• a first to eighth rotary shafts connected to the rotary elements of the first to fourth planetary gear devices;
• wherein the first rotary shaft is an input shaft directly connected to a second rotary element of the first planetary gear device, the second rotary shaft is directly connected to a first rotary element of the first planetary gear device, the third rotary shaft is directly connected to a third rotary element of the first planetary gear device and a third rotary element of the third planetary gear device, the fourth rotary shaft is directly connected to a first rotary element of the second planetary gear device, the fifth rotary shaft is directly connected to a second rotary element of the second planetary gear device, a second rotary element of the third planetary gear device and a third rotary element of the fourth planetary gear device, the sixth rotary shaft is directly connected to a third rotary element of the second planetary gear device, the seventh rotary shaft is directly connected to a first rotary element of the fourth planetary gear device, and the eighth rotary shaft is an output shaft directly connected to a first rotary element of the third planetary gear device and a second rotary element of the fourth planetary gear device;
• and wherein the six shifting elements include a first to fourth clutches and a first and second brakes, the first clutch is disposed between the second rotary shaft and the sixth rotary shaft, the second clutch is disposed between the second rotary shaft and the fourth rotary shaft, the third clutch is disposed between the first rotary shaft and the fourth rotary shaft, the fourth clutch is disposed between the sixth rotary shaft and the eighth rotary shaft, the first brake is disposed between the third rotary shaft and a transmission case, the second brake is disposed between the seventh rotary shaft and the transmission case.